Hamilton Public Health says the outbreak is impacting the Special Care Nursery and comes after three healthcare workers who work at the unit tested positive for COVID-19.
Public Health says one of the healthcare workers had no direct contact with patients and families, while the other two had either limited contact or contact while wearing a protective mask.
They were not symptomatic while caring for the babies or family.
Contact tracing is underway to ensure all babies, family members and staff/physicians who had direct contact with the positive healthcare workers are tested and appropriate measures will be taken to limit transmission.
Officials say no babies or parents in the unit are symptomatic and all are being monitored closely.
SJHH has created a separate space for infants who may have been exposed during this time period.
A deep cleaning of the unit is being done, and further infection prevention and control measures are in place.
The Special Care Nursery will continue to accept babies requiring care that are born at SJHH.